Transfer entire Jira platform from one account to another

For some time we made our Jira (10 seat version) available to our customer hence we removed our own projects and dedicated it to our customer. Our customer has now pruchased 50 Jira and 50 Agile user license. How can we restore the systems to an empty system which only contains the customers license or is there away to restore into in blank system and modify the account settings so it accepts the customers license. We have been researching almost a week. Andy advice is more then welcome.

No it isn't. We have several customers for which we host Jira. This was the first time we had to transfer an entire platform. What worked at the end was the option given upon full restore to replace the existing licenses.